Coking hydrocarbon oil



Aug. 18, 1936'. b. 1 THoMAs 2,051,354

COKING HYDROCARBON OIL Filed Sept. 13, 1953 INVENTOR DOAMLD L. THUN/1S ATTORNEY Patented Aug. 18, 1936 PATENT OFFICE 2,051,354 COKING HYDROCARBON OIL Donald L. Thomas, New York, N. Y., assignor to Gasoline Products Company,

Incorporated,

Newark, N. J., a corporation of Delaware Application September 13, 1933, Serial No. 689,254

4 Claims. (Cl. 202-18) eration, which latter operation is conducted in a separate piece of apparatus whose temperature may be independently controlled.

My invention contemplates withdrawing hydrocarbon oil residuum produced in a combined distilling and cracking operation and introducing it, while in a heated condition, into contact with a bath of molten metal maintained in an enlarged coking still. The heat transferred to the residuum from' the bath of molten metal decomposes it to coke which collects on the surface of the molten metal bath to be removed from the coking still either continuously or intermittently. Volatile constituents of the residuum may be separately removed, fractionated and condensed. Any liquid residuum adhering to the coke may be removed therewith and thereafter filtered out.

In order to make my invention more clearly understood, I have shown in the accompanying drawing, an apparatus for carrying the same into practical eiect without limiting the improvements in their useful applications to the particular constructions which, for the purpose of explanation, have been made the subject of illustration.

Figure 1 is an elevational view of an apparatus,

partly in section, capable of carrying out the invention.

Figure 2 is a horizontal cross-sectional view taken along line 2-2 of Figure 1.

Figure 3 is a horizontal cross-sectional view taken along line 3-3 of Figure 1.

Referring to the gures and more particularly to Figure l, there is shown a main vaporizer I for receiving oil to be 'distilled and avstreanr of oil that has been subjected to cracking. A separately red coking still 2 and a coke lter 3 are associated with the vaporizer I, the lter 3 sepa-- rating uncoked residuum from the coke discharged from the coking still 2 to permit the return thereof, as will be hereinafter explained,

for further treatment.

The vaporizer I may consist of a vertically placed steel drum of any suitable dimensions. This drum, for instance, may be about six feet in diameter and from about ten to fifteen feet in height. In the upper portion of the vaporizer I, there is located Aa circular cone shaped baille plate 4, firmly attached to a steel spider 5. The diameter of the circular baille plate 4,v which is centrally placed with reference to the vaporizer I, 5 is somewhat less than that of the vaporizer shell thereby providing an unobstructed annular space between the shell and the baille plate 4 for the free passage of hydrocarbon oil and gases. The annular space provided between the baille plate l0 4 and the shell may in actual construction be about 6 inches in width. Y

A conical member 6 may be located in an inverted position above the baille 4 and may be suitably joined to the sides of the vaporizer I to 15 shut off the upper portion thereof except for a central opening I. This central opening 'I is of materially less diameter than the baille plate 4, so that any liquid discharged therethrough will fall on the baule plate 4 and be distributed there- 20 by around the sides of the vaporizer shell to pass through the aforementioned annular space between the vaporizer shell and the baie plate 4.

By the construction just described, there is -formed a space 8 in the upper portion of the 25 vaporizer into which crude primary charging stock to be distilled may be delivered by way of a pipe 9 controlled by a suitable valve Il. The charging stock introducedthrough the pipe 9 passes through the opening 'I on to the baille 30 plate 4 by which it is distributed around the sides of the vaporizer.

A tubular distributing member I2, having four radially extending arms I3, may be located within the lower portion of the vaporizer I. The radially 35 k extending arms I3 may be provided on the upper side of each with a plurality of conical nozzles I4'communicating, with the interior of each arm in order that any liquid entering the arms I3 will be discharged through the nozzles I4 in an up- .40 ward direction. An overflow pipe I5 may be centrally positioned in the tubular distributing member I2 and suitably welded thereto. The overiiow pipe I5 may be spaced from the walls of the distributing member I2 to leave an annular space between the two in order that fluid delivered to this space by means of an oil pipe I6 controlled by valve I1, may enter the radial arms I3 of the member I2 and be discharged through the conical 5.0 nozzles I4 as clearly shown in Figure l. The overflow pipe I5 is preferably arranged to main. tain a considerable depth of liquid over the nozzles I4 so that when iluld is forcibly ejected from these nozzles in an upward direction it will carry 55 along with it overlying layers of liquid maintained in the bottom of thevvaporizer I.

'I'he fluid introduced through the pipe I6 to be ejected from the nozzles I4 may be the hot cracked stock coming from an oil cracking operation, for example, it may comprise the total stream of cracked products issuing from a cracking coil or passageway. The crude oil introduced into the upper portion of the vaporizer I through the line 9 will be subjected to intense and continually repeated contact with the upwardly rising vapors from the cracked stock in a somewhat spray form, thus bringing about rapid distillation of the liquid, the vapors from which, together with the cracked vapors, escape to a suitable rectifying and fractionating tower, not shown, through an opening I8 at the top of, the vaporizer. The central position of the overflow pipe I5 insures that all of the liquid entering the vaporizer shall at some time be brought under the entraining action of spraying jets thus insuring that no untreated residuum shall pass out through the overflow.

Valve I1 should be adjusted as necessary and optionally automatically to maintain a suicient pressure in the radial arms I3 to accomplish the desired spraying action through the nozzles I 4.

The residuum thus formed in the lower portion of the vaporizer I overflows through the pipe I5 suitably connected to a pipe I9 and may be picked up by a pump 2| and forced through a line 22, controlled by a valve 23, to the coking still 2. The coking still 2 may be of the shell still type and may be fired underneath in a well known manner as shown' in the drawing. While I have shown one way of heating the still 2, any well known heating arrangement may be employed.

The still 2 may be partially filled with a suitable fusible material, preferably an easily fusible metal or alloy. A tin-lead alloy may be used in accordance with my invention although lead alone may be used, if desired. In carrying out my inf vention the coking of the residuum is finished on the surface of the molten metal. The residuum to be coked may be introduced into the coking still 2 by a line 24, controlled by a valve 25, and therein contacted with the bath of molten metal maintained therein. Upon contacting the bath of molten metal, heat is imparted to the residuum thereby decomposing it into coke. It Will be evident that the coke as formed will be gradually dis, placed upwardly as it is being continuously added to below and will be nally forced through a dome 26 and connecting main 21 into the coke lter 3.

In accordance with my invention the residuum may be fed below the surface of the molten metal to thereby cause it to rise upwardly therethrough.

As shown in the drawing, suitable connections are provided for carrying out this method of operation. These connections may consist of a pipe 28, controlled by a valve 29, connected to a submerged distributing header 3|. It will be evident from these connections that all or a portion of the residuum may be directly introduced into the body of molten metal maintained in the still 2 through the distributing header 3|.

It may be desirable in operating in accordance with my invention, and particularly when the residuum is being introduced into the still through line 24, to introduce a small quantity of cracked products from the cracking operation vdirectly into the body of molten metal. As shown in the drawing, a pipe 32, controlled by a valve 33, may be suitablyconnected with the pipe 28 for introducing the cracked products into the distributing header 3| rIfhis particular methodof operation therein. The valves vis advaxitageous when all of the residuum is being and thus acts as a heat carrier for imparting this additional heat as Well as portions of its .own contained heat to the hydrocarbon material being coked on the surface of the molten metal. The highly heated vapors and gases passing-through the hydrocarbon material being converted into coke greatly lower the temperature at which the vaporizable material being formed in the coking still 2 can be removed from the material being coked.

The coke particles produced in accordance with my invention are prevented from uniting into a solid mass which would completely fill the upper part of the still by the violent agitation of the surface of the molten metal on which the coke rests. This violent agitation breaks up the masses into small units which may be allowed to accumulate in the free spaceof the still until it is full or nearly full to the top. It will be evident that as additional residuum is being introduced through the lines 24 and/or 28 the coke will be gradually displaced upwardly and will be finally forced through the dome 26 and the connecting main 21 plained.

Any liquid residuum not converted into coke and which may flow into the lter 2 with the coke may be separated therein from the coke and may be returned to the pump 2I by means of a line 34 which may be joined to a liquid discharge line'35 connected to the lower portion of the coke filter 3. During normal operation of the process the residuum collected in the coke filter 3 may be continuously withdrawn therefrom through the line 35 and reintroduced in a manner already de scribed into the coking still 2.

My invention further provides van arrangement wherein a constant supply of residuum may be introduced into the coking still regardless of whether a suiiicient supply is being produced in the vaporizer I. As shown in the drawing, an extraneous residuum or, if desired, a crude stockmay be introduced into the coking still 2 through a line 36 controlled by a valve 31 suitably connected to the branch line 24.

As shown in the drawing, the pipes 22 and 38, as well as the branch, pipe 24 may be joined by means of a four way connection 38 to tle line 28 lwhich in turn connects with the distributing header 3| submerged in the fusible metal. By this arrangement it is possible to 4direct either or both the residuum and the crude oil that may be introduced through line 36 directlyinto the molten material for vaporization and coking 23, 25,` 29 and 31 are provided to control the distribution of liquids being introduced into the still through the several paths previously outlined. l

In one manner of operation in accordance with my invention, valves 29 and 31 may be kept closed while valves 23 and 25 are kept open to admit the liquid residuum to the coking still as already 'explained When this method of operation is beinto the coke `filter 3 as previously exwill beclear from the arrangement of pipes hereinabove explained that the residuum and/or "they crude oil being-introduced into the coking still for illustrative purposes and any suitable means I 2 may follow several paths by obvious manipulation of the several valves disclosed in connecfI tion therewith. v

The coke filter 3 which may also serve as a temporary strorage vessel for the coke as formed, may be constructed as a cylindrical shell of any desired dimension. For instance, the shell may be some ten to fifteen feet in height and some ten to fifteen feet in diameter. The top of the coke filter 3 may be provided with a vapor discharge outlet 33 which connects with a suitable rectifying and fractionating tower, not shown, into which vapors evolved from the vaporizer 41 and the filter 3 may be passed. If desired, the coking still 2 may be provided with a separate vapor outlet which may be connected' with the outlet conducting the vaporsfrom the coke filter 3, the combined vapor streams being passed into the rectifying and fractionating column. 'I'he coke formed in the coking still 2 may be gradually forced by the continuous accumulation thereof through the coke transfer line or conduit 21 into the upper portion of Ithe coke filter 3 as clearly shown in the drawing. While I have shown a particular arrangement for removing the coke from the coke still 2 into the coke' filter 3, it is to be clearly understood that it is merely may be provided for accomplishing this purpose.

In accordance with my invention the coke may be accumulated in the coke still 2 until it reaches a point substantially at or near the dome 26. The coke thus accumulated may be flushed out 1 of the coke still 2 through the conduit 21 into the coke filter 3 by a suitable -ushing medium, such as hydrocarbon oil introduced into the still through the pipes connected therewith. When operating in accordance with this method. it will be apparent that the coke formed in the still 2 may be intermittently removed by utilizing the iiushing oil. The hydrocarbon oil used as a flushing medium and the coke removed from the cokingl still enter the coke filter 3 wherein the hydrocarbon flushing medium is filtered out and the coke permitted to dry or may be dried by extraneous sources such as a jet of -steam or hot gas passing through the coke body collected on thelters in the coke filter 3.

A plurality of filter elements 4 l Figure 3, in the form of thin metal sheets or bars of quadrant shape, are located in. the lower halfof the filter adjacent the wallsl thereof but in spaced relation thereto. The quadrant-shaped bars of the nlter elements 4I may each be provided with two projecting lugs 42 one at each end thereof. The bars when assembled are arranged so that the lugs 42 bear against the sides of the filter shell to provide anv annular space 43 between the lter elements and the sides of the filter. In this manner liquid can ow through the narrow aper' 'tie bars go through. the arrangement thus formlthe residuum line I9.

fromA deposit of material on the inner faceof the filter elements during a filtering operation, this Vmaterial may readily be dislodged and the elements restored -to active service by admitting cracked stock, while under superatmospheric leads into the annularspace 43 of they filter. By introducing the cracked products in the manpressure, from the pipe I6 into the line 34 which ner described, any material obstructing the in- A ner face of these openings may be dislodged. When carrying out this phase of the operation, valve 46 in line 41, which connects line I6 with line 34, will be opened to admit the cracked products to line 3.4 while valve 48 in the line 34 will be closed to prevent escape of the products into After the filter is thus cleared, the valves may be changed to their normal position for carrying out normal operation of the process.

In order to dump the collected coke in the filter there is provided a' removable door 43 through which the coke may be dischargedeith'er into a suitable tram or into a chute such as is used for ash removal, or any other suitable means.

Retaining rings 5l and 52 at the top and bottom of the filtering stack, respectively, close the space v43 and in connection with the tie bars 45 l fix the filtering stack firmly in its proper place in the lter shell from which it may be easily removed for cleaning and repairs when necessary.

While I have illustrated and described a single coke filter associated with the coking still 2. it is to be clearly understood that two or more such filters may be provided. In this manner while one is being filled another may be emptiedl and cleaned without stopping the operation of the still. The use of more than one coke filter in practicing my invention is important as the volume of coke to be handled is large. Preferably two such filters should be used in order to insure a short transfer line 21 between the still 2 and the filter 3, each filter being to the side of the still and in line with the delivery dome 26 which aordsv a symmetrical arrangement of the apparatus.

From the foregoing it will be apparent that I have invented aenovel method of coking hydrocarbon oils with the necessary apparatus for carrying out my invention. 'I'he use of molten metal as a heating medium is quite advantageous in accordance with my invention in that it insures that the distribution of heat throughout the body of hydrocarbon being coked will be as nearly uniform as possible and at the same time will prevent and possibly avoid overheating the still bottom as would likely occur if such a heating medium were not used as a protective means.

While 'my invention has been described in connection with coking of residual oil produced in the cracking of hydrocarbon oil, it is to be clearly understood that other carbonizingvma- ,terial may be coked in accordance therewith.

Carbonaceous material, preheated if desired,\

may be carbonized in accordance with`my invention by introducing it through a line comparable with either 24 or 28, the latter of which is connected to the distributing header 3| or in any other suitable manner falling within the scope of my invention. A

etc.V When such solid carbonaceous material is to be` treated it may be desirable to employ a ,different means for charging such material to the coking still. Instead of the pipes 24 and 28, a screw or chain-type feeder may be employed to feed the material to be coked. It will also be understood that heavy liquid hydrocarbon material may be coked or carbonized simultaneously with such solid carbonaceousmaterial.

If desired, the dome 26 may extend the entire width of the coking still 2. It may be desirable to curve the dome from its point of juncture with the coke still in an even curve to the top of the filter 3 where the outlet of the dome may be connected. In this manner, abrupt turns in the passage through which the coke may be removed are eliminated.

Obviously, many modifications and variations y of the invention, as hereinbefore set forth, may

be made without departing from the spirit and scope thereof, and therefore, only such limitations should be imposed as are indicated in the appended claims.

I claim:

' 1. A process for coking hyd! ocarbon oils which comprises maintaining a bod; of heavy oil in a vaporizing zone, continuously introducing a highly heated oil, at a temperature above the tempera-l ture of the body of oil, below the surface thereof to heat the body of oil to a temperature sufficiently high to accomplish distillation of the body of oil, causing the highly heated oil to pass through said body of oil at high velocity so as to continuously blow portions of the same as a spray into the free space of the vaporizing chamber, the unvaporized portion of said spray continuously falling back onto the body of oil from whence it came, withdrawing residual products i'rom said vaporizing zone and conducting them while in a heated condition to a coking zone, and contacting said residual products in said coking zone with highlyl heated molten metal to convert same into a coke residue.

2. A process for coking hydrocarbon oils which comprises maintaining a body of heavy oil in a vaporizing zone, continuouslyl introducing a highly vheated oil, at a temperature above the tern-` perature of the body of oil, below the surface thereof to heat the body of oil to a temperature suiliciently high to accomplish distillation of the body of oil, causing the highly heated oil to pass through said body of oil at high velocity so as to continuously blow portions of the same as a spray into the' free space of the vaporizing chamber, the unvaporized portion of .said spray continuously falling back onto the body of oil from whence it carne, withdrawing residual products from said vaporizing zone and conducting them while in a heated condition to a coking zone, and

passing said residual products entering said coking zone through a body of molten metal maintained therein at a temperature higher than the temperature of said entering residual products to thereby impart additional heat to said residual products and convert them to a coke residue in the coking zone.

`Ii. A process for coking hydrocarbon oils which comprises maintaining a body of heavy oil in a'. vaporizing zone, continuously introducing a highly heated oil, at a temperature above the temperature of the body of oil, below the surface thereof to heat the body of oil to a temperature suiliciently high to accomplish distillation of the body of oil, causing the highly heated oil to pass through said body of oil at high velocity so as to continuously blow portions of the same as a spray into the free space of the vaporlzing chamber, the unvaporized portion of said spray continuously falling back onto the body of oil from whence it came, withdrawing residual products from said vaporizing zone and conducting them while in a heated condition to a coking zone, passing said residual products entering said coking zone through a body of molten metal maintained therein at a temperature higher than the temperature of said entering residual products to thereby impart additional heat to said residual products and convert them to a coke residue in the coking zone, removing said coke residue from the coking zone and conducting it to a coke lter to separate out fluid remaining therein.

4. A process for coking hydrocarbon oils which comprises maintaining a body of heavy oil in a vaporizing zone, continuously introducing a highly heated oil, at a temperature above the temperature ofthe body of oil, below the surface thereof w to heat the body of oil to a temperature suiliciently high to accomplish distillation of the body of oil, causing the highly `heated oil to pass.l

through said body of oil at high velocity so as to continuously blow portions of the same as a spray yinto the freespace of the vaporizing chamber,

ing zone through a body of molten metal maintained therein at a temperature higher than the temperature of said entering residual products, introducing oil at cracking temperature intov intimate contact with the residual-products entering said coking zone, and decomposing the residual products to a coke residue in said coking zone by the heat imparted thereto from the body lof molten material and the oil at cracking temperature intimately contacted with said residual products.

' DONALD L. THOMAS. 

